[Bugfix] Bugs #371, #425.

Details:
1. Bug #371. Authoring: Timeline's edit button changes its size disproportionately.
2. Bug #425. Authoring: Timeline can't save 'infinite' value.
Fix #566: Create artifact loads the wrong image
Merge pull request #608 from alex-zen/bugfix371

[Bugfix] Bugs #371, #425.
Merge pull request #610 from javierluraschi/Fix566

Fix #566: Create artifact loads the wrong image
[BugFix] Fix #606: Unexpected behaviour of edit form